The growing demand for freshwater coupled with the decline in traditional water sources is driving the increased consumption of desalinated water. This paper introduces a comprehensive mathematical model that seeks to jointly optimize a multitude of strategic and tactical decisions within desalinated water systems while accounting for environmental alongside economic considerations. These decisions include the installation of new desalination plants, replacement of obsolete units, selection of desalination technologies, and the expansion of existing facilities as well as the location of new ones. Additionally, the model determines annual production levels in each plant, allocates water to various demand zones, and manages water levels in storage tanks. In order to validate the model, a realistic case study drawn from the United Arab Emirates is utilized. It is found that the operational cost components of desalination, transportation pipelines, and storage facilities are more significant than their capital cost counterparts. In addition, all replaced and new units employed Reverse Osmosis technology, which is in line with the emerging trend worldwide. Finally, the effect of increasing the capacity of new units and varying the carbon emissions tax on the relevant decisions as well as the overall cost is studied as part of the sensitivity analysis.